An analysis of incidents involving major hazards in the chemical industry

Some problems associated with assessing the safety performance of the Chemical Industry are discussed. Over 170 major incidents involving chemical plants world-wide have been collated and analysed for trends.The number of major incidents and the total number of people killed by such events are rising exponentially. The trend to increased size and complexity of installations does not appear to have led to more severe incidents in terms of deaths, although the analysis has limitations. Financial costs of major incidents are increasing at a rate way ahead of inflation but there is no correlation between these costs and the number of fatalities arising from these incidents. All this, together with additional considerations identified, is considered ample justification for the special attention directed at the study of Major Hazard installations.     

Molecular layer deposition of ZrO2-based organic-inorganic nanohybrid thin films for organic thin film transistors

Molecular layer deposition (MLD) technique can be used for preparation of various organic-inorganic nanohybrid superlattices at a gas-phase. The MLD method is a self-controlled layer-by-layer growth process under vacuum conditions, and is perfectly compatible with the atomic layer deposition (ALD) method. In this paper, we fabricated a new type organic-inorganic nanohybrid thin film using MLD method combined with ALD. A self-assembled organic layer (SAOL) was formed at 170 °C using MLD with repeated sequential adsorptions of CC terminated alkylsilane and zirconium hydroxyl with ozone activation. A ZrO₂ inorganic nanolayer was deposited at the same temperature using ALD with alternating surface-saturating reactions of Zr(OC(CH₃)₃)₄ and H₂O. The prepared SAOL-ZrO₂ organic-inorganic nanohybrid films exhibited good mechanical stability, excellent insulating properties, and relatively high dielectric constant k (~ 16). They were then used as a 23 nm-thick dielectric for low voltage pentacene-based thin film transistors, which showed a maximum field effect mobility of 0.63 cm²/V s, operating at − 1 V with an on/off current ratio of ~ 10³.     

Metalcones: hybrid organic-inorganic films fabricated using atomic and molecular layer deposition techniques

Hybrid organic-inorganic films can be deposited using atomic layer deposition (ALD) and molecular layer deposition (MLD) techniques. A special set of hybrid organic-inorganic films based on metal precursors and various organic alcohols yields metal alkoxide films that can be described as "metalcones." Many metalcone films are possible such as the "alucones" and "zincones" based on the reaction of trimethylaluminum and diethylzinc, respectively, with various organic alcohols such as ethylene glycol (EG). This paper reviews the previous work on metalcone MLD and discusses a variety of new metalcone systems. "Titanicones" are grown using TiCl4 and glycerol or EG and "zircones" are grown using zirconium tetra-tert-butoxide and EG. In addition, the organic alcohol can also be varied to change the properties within one metalcone family. For example, the glycerol triol precursor allows for more cross-linking and higher toughness in alucones than the EG diol precursor. Alloys can also be formed by combining metalcone MLD and metal oxide ALD. By varying the relative number of cycles of MLD and ALD, the composition and properties of the hybrid organic-inorganic films can be tuned from pure metalcone MLD to pure metal oxide ALD.     

Accident sequence analysis for sites producing and storing explosives

This paper presents a QRA-based approach for assessing and evaluating the safety of installations handling explosive substances. Comprehensive generic lists of immediate causes and initiating events of detonation and deflagration of explosive substances as well as safety measures preventing these explosions are developed. Initiating events and corresponding measures are grouped under the more general categories of explosion due to shock wave, explosion due to mechanical energy, thermal energy, electrical energy, chemical energy, and electromagnetic radiation. Generic accident sequences are developed using Event Trees. This analysis is adapted to plant-specific conditions and potentially additional protective measures are rank-ordered in terms of the induced reduction in the frequency of explosion, by including also uncertainty. This approach has been applied to 14 plants in Greece with very satisfactory results.     

On the quantification of the effects of organizational and management factors in chemical installations

The quantitative effects of organizational and management factors in chemical installations are assessed through a linking of the results of a safety management audit with the basic events of a quantified risk assessment (QRA). A safety management audit establishes the relative position of the organizational and management aspects of a particular chemical installation with respect to an ideal management scheme, and for a number of failure causes and failure prevention combinations. A quantitative risk analysis including detailed system analysis offers a plant-specific decomposition of the plant-damage-state frequencies into events like hardware failures, maintenance-related failures, operation-related failures and so on. The basic events incorporated in the QRA are then categorized into classes similar to those explored by the management audit and are quantitatively linked to the audit results. Knowledge of these quantitative links would allow for the reflection of the deficiencies or strengths that might exist in the safety management system on the quantitative risk indices. A case study of an ammonia storage facility that has been audited demonstrates that the sensitivity of the risk indices to the value of the quantitative links is extremely high and that hence great care should be exercised in assessing these links.     

Molecular layer deposition of an organic-based magnetic semiconducting laminate

Organic-based magnets are intriguing materials with unique magnetic and electronic properties that can be tailored by chemical methodology. By using molecular layer deposition (MLD), we demonstrate the thin film fabrication of V[TCNE: tetracyanoethylene](x), of the first known room temperature organic-based magnet. The resulting films exhibit improvement in surface morphology, larger coercivity (80 Oe), and higher Curie temperature/thermal stability (up to 400 K). Recently, the MLD method has been widely studied to implement fine control of organic film growth for various applications. This work broadens its application to magnetic and charge transfer materials and opens new opportunities for metal-organic hybrid material development and their applications in various multilayer film device structures. Finally, we demonstrate the applicability of the multilayer V[TCNE](x) as a spin injector combining LSMO, an standard inorganic magnetic semiconductor, for spintronics applications.     

Analytical simulation and PROFAT II: a new methodology and a computer automated tool for fault tree analysis in chemical process industries

Fault tree analysis (FTA) is based on constructing a hypothetical tree of base events (initiating events) branching into numerous other sub-events, propagating the fault and eventually leading to the top event (accident). It has been a powerful technique used traditionally in identifying hazards in nuclear installations and power industries. As the systematic articulation of the fault tree is associated with assigning probabilities to each fault, the exercise is also sometimes called probabilistic risk assessment. But powerful as this technique is, it is also very cumbersome and costly, limiting its area of application. We have developed a new algorithm based on analytical simulation (named as AS-II), which makes the application of FTA simpler, quicker, and cheaper; thus opening up the possibility of its wider use in risk assessment in chemical process industries. Based on the methodology we have developed a computer-automated tool. The details are presented in this paper.     

The german precursor study—methodology and insights

Probabilistic Safety Assessment (PSA) yields a systematic and quantitative prediction of possible accident scenarios at technical installations on the basis of data gained from the past experience on similar technical installations. Precursor studies are performed in order to make operational experience, as far as possible, available for support of PSAs. An Accident Sequence Precursor in a Nuclear Power Plant (NPP) is defined as an observed event scenario which could result, in coincidence with additional postulated events, in a potential severe core damage accident. In this paper, the methodology and the insights of the plant-specific German Precursor Study are explained in detail. As the results have demonstrated, the Precursor methodology is applicable for ranking of the safety significance of the observed events and for trending the plant risk level (described by the frequency of potential severe core damage accidents) versus operating time.     

An overview of highly porous oxide films with tunable thickness prepared by molecular layer deposition

This paper is a short review about the principle, preparation, and applications of ultra-thin oxide films prepared by molecular layer deposition (MLD). Porous oxide films, with well-defined porous structures and precisely controlled thicknesses down to several angstroms, can be prepared from dense organic/inorganic hybrid polymer films grown by MLD. The organic constituents in the film can be removed either by calcination at elevated temperatures or mild water etching at room temperature. Because of the layer-by-layer growth process for MLD, the deposited polymer films have regular structures and the removal of organic components from MLD polymer films produces uniform interconnected highly porous structures with a high surface area. For example, porous aluminum oxide films prepared by such a method have both micropores and mesopores with a BET surface area as high as 1250 m²/g. Examples of the versatility of the technique for fabrication of novel functional materials for various applications are discussed, including thermally stable, highly selective metal nanoparticle catalysts, defect-free inorganic membranes for gas separation, and photocatalytic layers prepared from titanium alkoxide MLD films.     

The ARIPAR project: analysis of the major accident risks connected with industrial and transportation activities in the Ravenna area

The paper describes the ARIPAR project aimed at the assessment of the major accident risks connected with storage, process and transportation of dangerous substances in the densely populated Ravenna area in Italy, which includes a large complex of chemical and petrochemical plants and minor industries, essentially distributed around an important commercial port. Large quantities of dangerous goods are involved in various transportation forms connected with the industrial and commercial activity of the port. The project started by making a complete inventory of fixed installations and transportation activities capable of provoking major fire, explosion and toxic release events; then relevant accident scenarios were developed for the single hazard sources; probabilities were assigned to the events and consequences were evaluated; finally iso-risk contours and F-N diagrams were evaluated both for the single sources and for the overall area. This required the development of a particular methodology for analysis of area risk and of associated software packages which allowed examination of the relative importance of the different activities and typologies of materials involved. The methodological approach and the results have proved to be very useful for the priority-ranking of risk mitigating interventions and physical planning in a complex area.     

Integrated pollution prevention and control in the surface treatment industries in Galicia (NW Spain)

The so-called IPPC Directive concerning integrated pollution prevention and control came into force 10 years ago affecting those industrial installations enumerated in its annex I, mainly characterized for being highly polluting sources. One of the innovations of this regulation is that the installations must have an integrated environmental permit granted by the competent authority of the region in which they are located. This environmental permit should include, among others, the Emission Limit Values (ELV) for the more relevant and potential pollutants which cannot be overcome, taking into account the Best Available Techniques (BAT). In Spain this Directive was transposed by the Law 16/2002 on July 2002. This paper shows the application of this law to the surface treatment sector using electrolytic or chemical procedures, encompassed as epigraph 2.6 in its annex I, in Galicia (NW Spain). An overview of the sector is made by analyzing the productive operations applied and their environmental aspects to consider the options to prevent and/or reduce the potential pollution. To assist this task a simple method to determine whether a technique can be considered or not as BAT is offered. Finally, a support guide to apply for the environmental permit was exclusively elaborated for this sector.     

The meaning of probability in probabilistic safety analysis

A Probabilistic Safety Analysis expresses uncertainty about the possible future damaging consequences of complex installations, such as chemical or nuclear plants, in terms of probabilities. Often these probabilities are interpreted as measures of physical properties of the installation and how it is operated, and a PSA is seen as a means to carry out these measurements. This view is useful for making comparative statements about the riskiness of installations, particularly when comparing them with standards. It is argued here, however, that this interpretation of probability is inconsistent with all the standard philosophical theories of probability, and so a different interpretation of PSA is necessary. We suggest, alternatively, that by using the standard subjective theory of probability, PSA may be seen as a tool for argument, rather than an objective representation of truth. In this interpretation the problems of expert choice and model validation become less problematic.     

营业线扩堑石方控制爆破安全快速施工技术

在营业线旁进行扩堑爆破施工 ,确保营业线设施以及行车的安全 ,是工程的关键。在株六复线各工点的扩堑施工中 ,采用了非预留隔墙的台阶或分层开挖方法。通过合理确定布孔参数、炸药单耗和起爆方式 ,降低了爆破震动 ,减少了飞石。利用自制的“炮被”覆盖炮孔 ,搭设钢管排架将爆区与营业线隔开 ,有效地避免了飞石、滚石和滑石对营业线的影响。文中对爆破参数确定、起爆网路设计、“炮被”的制做以及钢管排架的特点作了较详细的介绍 ,同时概述了这项研究所取得的技术经济效果     

营业线扩堑石方控制爆破安全快速施工技术

在营业线旁进行扩堑爆破施工 ,确保营业线设施以及行车的安全 ,是工程的关键。在株六复线各工点的扩堑施工中 ,采用了非预留隔墙的台阶或分层开挖方法。通过合理确定布孔参数、炸药单耗和起爆方式 ,降低了爆破震动 ,减少了飞石。利用自制的“炮被”覆盖炮孔 ,搭设钢管排架将爆区与营业线隔开 ,有效地避免了飞石、滚石和滑石对营业线的影响。文中对爆破参数确定、起爆网路设计、“炮被”的制做以及钢管排架的特点作了较详细的介绍 ,同时概述了这项研究所取得的技术经济效果     

Minimizing energy consumption via multiple installations aggregate production planning

As most of the energy in today’s scenario is still relied on fossil fuels and it causes a negative impact on the environment, hence energy saving should be considered as an important element of production planning. However, energy-efficient production planning should also be cost-efficient. There are technologies that are expected to become affordable in due time frame. Such affordability and expected technology advancements can be included in production planning using multiple installations of production facilities. In this paper, an insight-based graphical method is proposed for multiple installations aggregate production planning that minimizes energy consumption of production facilities. The methodology is capable of accounting capital cost affordability as well. Application of the proposed methodology on illustrative examples demonstrates that significant energy reduction can be achieved by multiple installations production planning.     

Method of Protection and Diagnostics of the Combustion Chamber Wall on Exposure to a High‐Intensity Heat Flux

In the present work, consideration is given to the method of thermal protection of the walls of highpower installations (plasmatrons and gasphase nuclear reactors), made of porous refractory materials, with the use of gasdust protection. The algorithm for determining the mechanical, thermal, and thermophysical characteristics of the porous wall of a combustion chamber from the measured increase in the pressure on the exterior surface of the wall is given.     

Technical and economic characteristics of processes for water detritiation by chemical isotope exchange in the water-hydrogen system

To solve the problem of light-water waste ditritiation, comparative calculations were performed for the two-temperature and one-temperature installations whose operation is based on chemical isotope exchange between hydrogen and water. The two-temperature installation ensures lower power consumption, but exceeds the one-temperature installation in size by an order of magnitude and more. A scheme of a combined installation was suggested, involving the fractional vacuum distillation of water in the step of waste detritiation and successively two- and one-temperature procedures of chemical isotope exchange in the water-hydrogen system in the step of tritium concentration.     

电镀废水处理工程设计实例

在实际工程中,采用何种方法处理电镀废水,需要根据具体条件加以考虑.讨论了含铬废水、含氰废水、酸碱重金属废水的处理方法和原理,结合西安某厂电镀废水处理的具体改造工程,设计了一套电镀废水的处理工艺流程,确定以化学还原法处理含铬废水,以碱性氯化法处理含氰废水,以碱性沉淀法处理酸碱重金属废水.整个工程处理设备较少、造价低、效果稳定,能承受大水量和高浓度负荷的冲击,出水水质达到国家污水综合排放标准.     

letter to the editor

A non-destructive method of checking cable identity and continuity in strain gauge installations is described. It is particularly applicable to completed systems having a large number of remote gauges.     

Evaluation of VOC recovery strategies

Many manufactured items receive surface coatings for decoration and/or protection against damage. In a number of places along the production line emissions of (VOC) Volatile Organic Compounds can occur. Because VOC are a major contributor to photochemical smog, control of VOC emissions is a major concern for the industries' commitment to the environment. Approaches for process optimisation have a long tradition within chemical and process engineering for the systematic identification of cost- and resource-efficient production options. The challenge in the context of supply chain management is the optimal recovery and reuse of materials not only for single substances or energy flows in large chemical installations, but also for smaller production processes and various mass and energy flows within and between enterprises. Based on a case study from the industrial coating of bicycle frames, an approach for Multi Objective Pinch Analysis (MOPA) for the evaluation of overall recovery potentials for energy, water and VOC is presented. Moreover, a metric for resource efficiency is introduced as a measure for the possible savings potential and for the savings ultimately realised. This integrated approach requires a tight coupling of mass, energy, economic and environmental assessment methods and demands a highly interdisciplinary approach.